1. Field of the Invention
The present invention relates to timing lights for monitoring the timing of events in internal combustion engines. The invention is particularly concerned with timing lights for use with diesel engines.
2. Description of the Prior Art
High intensity strobe lights, called timing lights, are used in conjunction with timing marks or indicia on the block and on an adjacent rotating part of an internal combustion engine for timing the ignition of the no. 1 cylinder. In spark-ignited engines, the timing light is triggered by the no. 1 spark plug signal. However, in the case of diesel engines, timing is more difficult, since there is no spark plug from which to obtain the ignition signal.
Timing lights for diesel engines have been triggered by pressure sensors adapted to mate with the glow plug receptacle of a diesel engine cylinder to sense the pressure resulting from combustion in the cylinder. Also, trigger circuits have been provided for detecting the point in time at which an injector nozzle begins to open to inject fuel into the cylinder. However, in many cases, the no. 1 cylinder is not readily accessible.
It is known to utilize a vibration sensor, such as a knock sensor, to detect engine vibrations resulting from the pressure of cylinder combustion. However, such sensors detect the ignition events for all cylinders whereas, for purposes of triggering a timing light, only the no. 1 cylinder ignition event is of interest.